# Protocol Buffers - Google's data interchange format
# Copyright 2008 Google Inc.  All rights reserved.
# https://developers.google.com/protocol-buffers/
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
#     * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# TODO(robinson): We should just make these methods all "pure-virtual" and move
# all implementation out, into reflection.py for now.


"""Contains an abstract base class for protocol messages."""

__author__ = 'robinson@google.com (Will Robinson)'


class Error(Exception):
    """Base error type for this module."""
    pass


class DecodeError(Error):
    """Exception raised when deserializing messages."""
    pass


class EncodeError(Error):
    """Exception raised when serializing messages."""
    pass


class Message(object):
    """Abstract base class for protocol messages.

    Protocol message classes are almost always generated by the protocol
    compiler.  These generated types subclass Message and implement the methods
    shown below.
    """

    # TODO(robinson): Link to an HTML document here.

    # TODO(robinson): Document that instances of this class will also
    # have an Extensions attribute with __getitem__ and __setitem__.
    # Again, not sure how to best convey this.

    # TODO(robinson): Document that the class must also have a static
    #   RegisterExtension(extension_field) method.
    #   Not sure how to best express at this point.

    # TODO(robinson): Document these fields and methods.

    __slots__ = []

    #: The :class:`google.protobuf.descriptor.Descriptor` for this message type.
    DESCRIPTOR = None

    def __deepcopy__(self, memo=None):
        clone = type(self)()
        clone.MergeFrom(self)
        return clone

    def __eq__(self, other_msg):
        """Recursively compares two messages by value and structure."""
        raise NotImplementedError

    def __ne__(self, other_msg):
        # Can't just say self != other_msg, since that would infinitely recurse. :)
        return not self == other_msg

    def __hash__(self):
        raise TypeError('unhashable object')

    def __str__(self):
        """Outputs a human-readable representation of the message."""
        raise NotImplementedError

    def __unicode__(self):
        """Outputs a human-readable representation of the message."""
        raise NotImplementedError

    def MergeFrom(self, other_msg):
        """Merges the contents of the specified message into current message.

        This method merges the contents of the specified message into the current
        message. Singular fields that are set in the specified message overwrite
        the corresponding fields in the current message. Repeated fields are
        appended. Singular sub-messages and groups are recursively merged.

        Args:
          other_msg (Message): A message to merge into the current message.
        """
        raise NotImplementedError

    def CopyFrom(self, other_msg):
        """Copies the content of the specified message into the current message.

        The method clears the current message and then merges the specified
        message using MergeFrom.

        Args:
          other_msg (Message): A message to copy into the current one.
        """
        if self is other_msg:
            return
        self.Clear()
        self.MergeFrom(other_msg)

    def Clear(self):
        """Clears all data that was set in the message."""
        raise NotImplementedError

    def SetInParent(self):
        """Mark this as present in the parent.

        This normally happens automatically when you assign a field of a
        sub-message, but sometimes you want to make the sub-message
        present while keeping it empty.  If you find yourself using this,
        you may want to reconsider your design.
        """
        raise NotImplementedError

    def IsInitialized(self):
        """Checks if the message is initialized.

        Returns:
          bool: The method returns True if the message is initialized (i.e. all of
          its required fields are set).
        """
        raise NotImplementedError

    # TODO(robinson): MergeFromString() should probably return None and be
    # implemented in terms of a helper that returns the # of bytes read.  Our
    # deserialization routines would use the helper when recursively
    # deserializing, but the end user would almost always just want the no-return
    # MergeFromString().

    def MergeFromString(self, serialized):
        """Merges serialized protocol buffer data into this message.

        When we find a field in `serialized` that is already present
        in this message:

        -   If it's a "repeated" field, we append to the end of our list.
        -   Else, if it's a scalar, we overwrite our field.
        -   Else, (it's a nonrepeated composite), we recursively merge
            into the existing composite.

        Args:
          serialized (bytes): Any object that allows us to call
            ``memoryview(serialized)`` to access a string of bytes using the
            buffer interface.

        Returns:
          int: The number of bytes read from `serialized`.
          For non-group messages, this will always be `len(serialized)`,
          but for messages which are actually groups, this will
          generally be less than `len(serialized)`, since we must
          stop when we reach an ``END_GROUP`` tag.  Note that if
          we *do* stop because of an ``END_GROUP`` tag, the number
          of bytes returned does not include the bytes
          for the ``END_GROUP`` tag information.

        Raises:
          DecodeError: if the input cannot be parsed.
        """
        # TODO(robinson): Document handling of unknown fields.
        # TODO(robinson): When we switch to a helper, this will return None.
        raise NotImplementedError

    def ParseFromString(self, serialized):
        """Parse serialized protocol buffer data into this message.

        Like :func:`MergeFromString()`, except we clear the object first.

        Raises:
          message.DecodeError if the input cannot be parsed.
        """
        self.Clear()
        return self.MergeFromString(serialized)

    def SerializeToString(self, **kwargs):
        """Serializes the protocol message to a binary string.

        Keyword Args:
          deterministic (bool): If true, requests deterministic serialization
            of the protobuf, with predictable ordering of map keys.

        Returns:
          A binary string representation of the message if all of the required
          fields in the message are set (i.e. the message is initialized).

        Raises:
          EncodeError: if the message isn't initialized (see :func:`IsInitialized`).
        """
        raise NotImplementedError

    def SerializePartialToString(self, **kwargs):
        """Serializes the protocol message to a binary string.

        This method is similar to SerializeToString but doesn't check if the
        message is initialized.

        Keyword Args:
          deterministic (bool): If true, requests deterministic serialization
            of the protobuf, with predictable ordering of map keys.

        Returns:
          bytes: A serialized representation of the partial message.
        """
        raise NotImplementedError

    # TODO(robinson): Decide whether we like these better
    # than auto-generated has_foo() and clear_foo() methods
    # on the instances themselves.  This way is less consistent
    # with C++, but it makes reflection-type access easier and
    # reduces the number of magically autogenerated things.
    #
    # TODO(robinson): Be sure to document (and test) exactly
    # which field names are accepted here.  Are we case-sensitive?
    # What do we do with fields that share names with Python keywords
    # like 'lambda' and 'yield'?
    #
    # nnorwitz says:
    # """
    # Typically (in python), an underscore is appended to names that are
    # keywords. So they would become lambda_ or yield_.
    # """
    def ListFields(self):
        """Returns a list of (FieldDescriptor, value) tuples for present fields.

        A message field is non-empty if HasField() would return true. A singular
        primitive field is non-empty if HasField() would return true in proto2 or it
        is non zero in proto3. A repeated field is non-empty if it contains at least
        one element. The fields are ordered by field number.

        Returns:
          list[tuple(FieldDescriptor, value)]: field descriptors and values
          for all fields in the message which are not empty. The values vary by
          field type.
        """
        raise NotImplementedError

    def HasField(self, field_name):
        """Checks if a certain field is set for the message.

        For a oneof group, checks if any field inside is set. Note that if the
        field_name is not defined in the message descriptor, :exc:`ValueError` will
        be raised.

        Args:
          field_name (str): The name of the field to check for presence.

        Returns:
          bool: Whether a value has been set for the named field.

        Raises:
          ValueError: if the `field_name` is not a member of this message.
        """
        raise NotImplementedError

    def ClearField(self, field_name):
        """Clears the contents of a given field.

        Inside a oneof group, clears the field set. If the name neither refers to a
        defined field or oneof group, :exc:`ValueError` is raised.

        Args:
          field_name (str): The name of the field to check for presence.

        Raises:
          ValueError: if the `field_name` is not a member of this message.
        """
        raise NotImplementedError

    def WhichOneof(self, oneof_group):
        """Returns the name of the field that is set inside a oneof group.

        If no field is set, returns None.

        Args:
          oneof_group (str): the name of the oneof group to check.

        Returns:
          str or None: The name of the group that is set, or None.

        Raises:
          ValueError: no group with the given name exists
        """
        raise NotImplementedError

    def HasExtension(self, extension_handle):
        """Checks if a certain extension is present for this message.

        Extensions are retrieved using the :attr:`Extensions` mapping (if present).

        Args:
          extension_handle: The handle for the extension to check.

        Returns:
          bool: Whether the extension is present for this message.

        Raises:
          KeyError: if the extension is repeated. Similar to repeated fields,
            there is no separate notion of presence: a "not present" repeated
            extension is an empty list.
        """
        raise NotImplementedError

    def ClearExtension(self, extension_handle):
        """Clears the contents of a given extension.

        Args:
          extension_handle: The handle for the extension to clear.
        """
        raise NotImplementedError

    def UnknownFields(self):
        """Returns the UnknownFieldSet.

        Returns:
          UnknownFieldSet: The unknown fields stored in this message.
        """
        raise NotImplementedError

    def DiscardUnknownFields(self):
        """Clears all fields in the :class:`UnknownFieldSet`.

        This operation is recursive for nested message.
        """
        raise NotImplementedError

    def ByteSize(self):
        """Returns the serialized size of this message.

        Recursively calls ByteSize() on all contained messages.

        Returns:
          int: The number of bytes required to serialize this message.
        """
        raise NotImplementedError

    @classmethod
    def FromString(cls, s):
        raise NotImplementedError

    @staticmethod
    def RegisterExtension(extension_handle):
        raise NotImplementedError

    def _SetListener(self, message_listener):
        """Internal method used by the protocol message implementation.
        Clients should not call this directly.

        Sets a listener that this message will call on certain state transitions.

        The purpose of this method is to register back-edges from children to
        parents at runtime, for the purpose of setting "has" bits and
        byte-size-dirty bits in the parent and ancestor objects whenever a child or
        descendant object is modified.

        If the client wants to disconnect this Message from the object tree, she
        explicitly sets callback to None.

        If message_listener is None, unregisters any existing listener.  Otherwise,
        message_listener must implement the MessageListener interface in
        internal/message_listener.py, and we discard any listener registered
        via a previous _SetListener() call.
        """
        raise NotImplementedError

    def __getstate__(self):
        """Support the pickle protocol."""
        return dict(serialized=self.SerializePartialToString())

    def __setstate__(self, state):
        """Support the pickle protocol."""
        self.__init__()
        serialized = state['serialized']
        # On Python 3, using encoding='latin1' is required for unpickling
        # protos pickled by Python 2.
        if not isinstance(serialized, bytes):
            serialized = serialized.encode('latin1')
        self.ParseFromString(serialized)

    def __reduce__(self):
        message_descriptor = self.DESCRIPTOR
        if message_descriptor.containing_type is None:
            return type(self), (), self.__getstate__()
        # the message type must be nested.
        # Python does not pickle nested classes; use the symbol_database on the
        # receiving end.
        container = message_descriptor
        return (_InternalConstructMessage, (container.full_name,),
                self.__getstate__())


def _InternalConstructMessage(full_name):
    """Constructs a nested message."""
    from lark_oapi.ws.pb.google.protobuf import symbol_database  # pylint:disable=g-import-not-at-top

    return symbol_database.Default().GetSymbol(full_name)()
